The invention relates generally to internal combustion engines, and more particularly, to two-stroke piston-ported engines. Such engines have, in the past, commonly employed the incoming fuel/air mixture to scavenge the exhaust gases from the cylinder with the result that incoming charge was often, in part, discharged unburnt through the exhaust system in the atmosphere, thereby providing a pollution problem as well as adversely affecting fuel economy.
Disclosed in the Scott U.S. Pat. No. 968,200 issued Aug. 23, 1910, and in the Springer U.S. Pat. No. 980,134 issued Dec. 27, 1910, are two-stroke internal combustion engines in which scavenging air is sucked into a transfer passage and delivered from the transfer passage into the cylinder ahead of delivery of fuel/air mixture through the transfer passage from the crankcase.
Attention is also directed to the following United States Patents which disclose delivery of scavenging air to the cylinder prior to delivery to the cylinder of fuel/air mixture.
______________________________________ Patent Issue Date ______________________________________ Brehm 854,981 May 28, 1907 Easthope 976,858 November 29, 1910 Bachle & Krebs 1,115,481 November 3,1914 Deacon 1,511,112 October 7,1924 Mansoff 2,381,832 August 7,1945 ______________________________________
Attention is also directed to my earlier U.S. Pat. Nos. 3,312,205 issued Apr. 1967, and 2,966,900 issued Jan. 3, 1961, which disclose other forms of prior two-stroke internal combustion engines.